Heat and Mass Flow from Thermal Areas in and Adjacent to Lassen Volcanic National Park, California, USA

Abstract

Average rates of heat loss from eight steam-heated thermal areas in Lassen Volcanic National Park, California, range from 0.1 MW to 37 MW and total 1 MW. The total rate of upflow of steam from underlying vapor-dominated required to supply this heat loss is about 40 Measurements of chloride flux in streams draining from the Park indicate that the total rate of liquid discharge from the Lassen geothermal system is also about 40 Thus, the measured ratio of steam upflow to liquid outflow is approximately 1.0. This value is significantly greater than values predicted by a previously published numerical model of the Lassen system ratios which involved a deep upflow of 260?C water that boils as it rises. This discrepancy suggests either that additional thermal-water discharge remains undetected or that alternative models need to be considered for the Lassen geothermal system.